When examining cache behaviour on our web site I got a very confusing result - my Internet Explorer 11 browser did not cache any files at all. The cache settings in the Internet Option is set to "Check for newer versions of stored pages: Automatically".
Investigating further with IE developer tool, all files were requested without an "if-modified-since" HTTP header, which of course caused the server to return the complete file with a 200 status result. Expected behaviour would be that IE should send an "if-modified-since" header, and the server then responding with a 304 (Not modified) status telling the browser to use the cached copy.
The same behavior occurs for all web sites I have tried.
I then used browserstack.com to open up a remote IE11 on a Windows 7-machine. Same result, no files are cached. However, on a Windows 8.1 machine, IE11 caches the files and sends a "if-modified-since" header, causing in 304 responses.
I include example request and response headers:
Request from Windows 7 / IE11:
Request:GET /EdUwb.png HTTP/1.1
Accept:image/png, image/svg+xml, image/*;q=0.8, */*;q=0.5
Referer:http://stackoverflow.com/
Accept-Language:sv-SE
User-Agent:Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko
Accept-Encoding:gzip, deflate
Host:i.stack.imgur.com
Connection:Keep-Alive
Response from Windows 7 / IE11:
Response:HTTP/1.1 200 OK
Date:Wed, 05 Aug 2015 14:30:43 GMT
Content-Type:image/png
Content-Length:3635
Connection:keep-alive
Set-Cookie:__cfduid=dfbb24e8f5badb07e8f2bbd969590320b1438785043; expires=Thu, 04-Aug-16 14:30:43 GMT; path=/; domain=.imgur.com; HttpOnly
Cache-Control:public, max-age=315360000
ETag:"c5d00c1be2583713eca1d0ad1efdb914"
Expires:Sat, 02 Aug 2025 14:30:43 GMT
Last-Modified:Thu, 02 Apr 2015 19:36:41 GMT
x-amz-version-id:Rmrsr2WfDsdFppBa_Ju10BC3Y52.bglA
CF-Cache-Status:HIT
Vary:Accept-Encoding
Server:cloudflare-nginx
CF-RAY:2113339ae74b0a48-ARN
Request from Windows 8.1 / IE11:
Request:GET /EdUwb.png HTTP/1.1
Accept:image/png, image/svg+xml, image/*;q=0.8, */*;q=0.5
Referer:http://stackoverflow.com/
Accept-Language:en-US
User-Agent:Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; rv:11.0) like Gecko
Accept-Encoding:gzip, deflate
Host:i.stack.imgur.com
If-Modified-Since:Thu, 02 Apr 2015 19:36:41 GMT
If-None-Match:"c5d00c1be2583713eca1d0ad1efdb914"
Connection:Keep-Alive
Response from Windows 8.1 / IE11:
Response:HTTP/1.1 304 Not Modified
Content-Type:image/png
Content-Length:3635
ETag:"c5d00c1be2583713eca1d0ad1efdb914"
x-amz-version-id:Rmrsr2WfDsdFppBa_Ju10BC3Y52.bglA
CF-Cache-Status:HIT
Vary:Accept-Encoding
CF-RAY:21133083e7920c5f-AMS
Expires:Sat, 02 Aug 2025 14:28:19 GMT
Last-Modified:Thu, 02 Apr 2015 19:36:41 GMT
Has anyone got an idea why the file is not cached on Windows 7?
IE11 devtools has a "Always refresh from server" option that is on by default. You have to turn this off to be able to watch caching happen in the devtools.
Deselect the below setting in IE:
Internet Options > Advanced tab > Settings > Security > Empty Temporary Internet Files folder when browser is closed.
Visit here for more information: http://muthukumarsankaralingam.blogspot.com/2018/08/configure-internet-explorer-to-read.html
来源：https://stackoverflow.com/questions/31835767/ie11-on-windows-7-does-not-cache-files